Multiplexing switch



June l, 1954 c. W. BEssERER, JR 2,680,163'

MULTIPLEXING SWITCH Filed June l1, 1952 IIIIIIII A r roms vs PatentedJune 1, 1954 MULTIPLEXING SWITCH Carl W. Besserer, Jr.,

Silver Spring, Md., assigner to the United States of America asrepresented by the Secretary of the Navy Application June 11, 1952,Serial No. 292,868

2 Claims. l

The present invention relates generally to switching devices and moreparticularly to an improved multiplexing switch for use on a multiplesubcarrier telemetering system` The increased use of telemetering in theeX- perimentation and development of remotely controlled aircraft hasbrought about an ever increasing demand for systems having greaterintelligence carrying capacities. One of the factors limiting theintelligence carrying capacity of a telemetering system is the abilityof the switching apparatus of the system to handle increased traiiicrequirements. The purpose of a multiplexing switch is to alternatelyapply a plurality of subcarrier signals, which are indications of theforces desired to be ascertained, to the modulator unit of a radiofrequency transmitter rapidly and in sequential order. Due to thelimitations of known switches, such as the speed with which switchingcan be attained, and f the generation of noise due to chattering, etc.,the number of subcarrier to signal channels usable with a singletransmitter has been unduly restricted.

It is therefore one object of the present invention to provide amultiplexing switch which is capable of switching at very high speeds.

Another object of the invention is to provide a high speed multiplexingswitch wherein the generation of noise within the switch is greatlyreduced.

Other objects and many of the attendant aclvantages of this inventionwill be appreciated readily as the same becomes understood by referenceto the following detailed description, when considered in connectionwith the accompanying drawings, wherein;

Fig. 1 is an axial section of the switch, partly in elevation;

Fig. 2 is an end elevation of the switch.

Referring now to Fig. 1, the multiplexing switch comprises a cylindricalcasing II having teeth I2 projecting from its inner circumferentialsurface so as to form an annular internal gear [2a.

A plurality of pairs of terminals I3 project through the casing II atspaced intervals about the periphery of said casing and terminate incompanion contacts I4 positioned in the grooves between the teeth I2 ofthe gear I2a. As best seen in Fig. l, the terminals of each pair are inparallel spaced relation. These terminals I3 are secured to the casingby nuts I5.

Attached to the casing II, as by screws I6, and supporting a cylindricalhousing Il, is a circular plate I8 formed with an axial opening I9. Asmall drive motor 2I including a drive shaft 22 is supported within thehousing I8, and has its driveshaft 22 projecting through the opening I9and axially into the casing II. Fastened to the driveshaft 22 by alocking bolt 23 and extending radially from said driveshaft is a U-shaped bracket which denes a rotor 2li for the switch. The bracket whichdeiines the rotor 2t includes legs 25 connected by a bight 26, the freeends of said legs being slotted at 27 to receive a trunnion 28 and aninsulating sleeve 3B about said trunnion.

Rotatably mounted on the trunnion 23 is a star-shaped contact element 29made of conductive material and having cogs 3| which mesh with the teethI2 of the gear I 2a to bridge a companion pair of contacts of theterminals I3. rlwo wire springs 32 are formed with looped centralportions 33 which encircle the ends ci the trunnion, and arms 34 bowedoutwardly from each other and terminating in hooks 35, which areengageable in apertures 36 in the rotor 2t. Retaining rings 3l cooperatewith annular grooves 38 formed in each end of the trunnion 23 to holdsaid trunnion, and the springs 32 in their intended positions.

In operation, each pair of terminals I3 or as many pairs as there arecircuits to serve, is electrically connected into its respectivecircuit. Upon the motor 2I being energized, the starshaped element 26rolls in a planetary path about the inner circumference of the casingII. The switching action is accomplished by the cogs 3l which mesh withthe teeth I2 of the gear I2a and sequentially short-circuit the contactsof each pair of terminals I3.

The springs 32, because of the bowed shape of their arms, urge the cogs3I of the star shaped gear 2S outwardly to rmly engage the teeth I2 ofthe casing II and thereby prevent chattering.

A switch of the type described has the unusual capacity of consecutivelyserving a great many circuits in a short interval of time.Notwithstanding the high speed operation of the switch, chattering andother noises which are characteristic of the prior high speed switchesare eiTectively reduced.

Obviously many other embodiments other than that shown and described arepossible without digressing from the teachings of the invention definedin the appended claims. For example, the cylindrical casing I Iincluding the gear teeth I2 may be extended to accommodate ranks ofterminals in annular series each rank comprising a plurality of pairs ofterminals I3 and their companion contacts I4. A bank of rotor assembliesthen may be arranged on a common driveshaft to accomplish the switchingaction. Therefore, the foregoing detailed description is to be construedonly as illustrative of this invention and not as limiting upon theappended claims.

What is claimed is:

l. A multiplexing switch, comprising, an internal gear, a plurality ofelectric contact members disposed in the troughs of said gear, said=mem+bers being insulated romeachother, a driveshaft concentric with saidgear, a UI-shaped'rotor, having two legs connected by a bight and a slotformed in the extremity of each leg, said rotor being mounted on saiddriveshatso that-the legs extend radially from said shaft, atrunnionvsupported in the slots of said rotor, a star-shaped contactelement rotatably mounted on .said ,trun- 20 nion and insulated'.therefrom, spring means mounted onv said rotor and bearing upon saidtrunnion to urge said'contact elementinto rm 4 engagement with said gearand said contact members, and means for rotating said shaft.

2. In a multiplexing switch for sequentially closing a plurality ofelectric circuits, a mounting, a plurality of terminals arranged in anannularly spaced series on the mounting, and contact meansengageableWithsaid terminals, said contactrneans. including adriveshaft, aU-shaped rotor on the driveshaft having a slot orxned in the extremityof each leg of said rotor, a trunnion supported in the slots of thelegs, a contact elementl on the trunnion, and spring meanstensionedbetwcen-the trunnion and the legs of the rotor. for' urgingthecontact element into selective engagement with said terminals.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 916,649.' Backev Mar. 30, 1909 1,197,537 Parker Sept. 5, 19162,399,022: Harkness Apr. 23, 1946

